From: Oleg Nesterov <oleg@tv-sign.ru>
To: "Paul E. McKenney" <paulmck@us.ibm.com>,
Dipankar Sarma <dipankar@in.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: rcu_do_batch: rcu_data->qlen is not irq safe
Date: Sun, 10 Sep 2006 19:08:20 +0400 [thread overview]
Message-ID: <20060910150820.GA7433@oleg> (raw)
rcu_do_batch() decrements rdp->qlen with irqs enabled.
This is not good, it can also be modified by call_rcu()
from interrupt.
So, is it worth fixing? The problem is mostly theoretical.
If yes, is it ok to use local_t ? Iirc, the were some
problems with local_t on some arches. Sometimes it is
just atomic_t ...
Otherwise, we can update ->qlen after the main loop,
local_irq_disable();
rdp->qlen -= count;
local_irq_enable();
What dou you think?
Oleg.
next reply other threads:[~2006-09-10 15:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-10 15:08 Oleg Nesterov [this message]
2006-09-10 20:58 ` rcu_do_batch: rcu_data->qlen is not irq safe Dipankar Sarma
2006-09-10 21:27 ` Oleg Nesterov
2006-09-10 21:32 ` [PATCH] rcu_do_batch: make ->qlen decrement " Oleg Nesterov
2006-09-10 22:17 ` Dipankar Sarma
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